Khan.scratchpad.disable(); To move up to the maestro level in his piano school, Brandon needs to master at least $109$ songs. Brandon has already mastered $15$ songs. If Brandon can master $4$ songs per month, what is the minimum number of months it will take him to move to the maestro level?
Explanation: To solve this, let's set up an expression to show how many songs Brandon will have mastered after each month. Number of songs mastered $=$ $ $ Months at school $\times$ Songs mastered per month $+$ Songs already mastered Since Brandon Needs to have at least $109$ songs mastered to move to maestro level, we can set up an inequality to find the number of months needed. Number of songs mastered $\geq 109$ Months at school $\times$ Songs mastered per month $ +$ Songs already mastered $\geq 109$ We are solving for the months spent at school, so let the number of months be represented by the variable $x$ We can now plug in: $x \cdot 4 + 15 \geq 109$ $ x \cdot 4 \geq 109 - 15 $ $ x \cdot 4 \geq 94 $ $x \geq \dfrac{94}{4} \approx 23.50$ Since we only care about whole months that Brandon has spent working, we round $23.50$ up to $24$ Brandon must work for at least 24 months.